The present invention relates to an information processing system for a bidirectional information transmission system using a broadband ISDN, a cable television network, a public telephone network, or the like. More particularly, the invention relates to an information transmission method and information storage method capable of transmitting information while taking into consideration a change in the transmission capacity of a network.
In an information provider system using a telephone network, for example, there are services for providing various types of voice information and video information by using the idle time of a telephone line. A video communications system is constructed of central equipment for transmitting video information, home equipment including home peripheral terminals and video receivers, and exchange center equipment interconnecting central equipment and home equipment.
The characteristic features of a video communications system are as follows. Information can be unidirectionally provided at a low cost. Video information may be used for supplementing voice information. Interactive services and information retrieval services can be provided by using a bidirectional transmission function of each terminal equipment.
The above-described communications system uses a constant transmission rate of information to be transmitted over a communication line. As a result, even if the room capacity of the communication line is sufficient, it takes the same time to transmit the same amount of information to each subscriber.
Although the above-described communications system provides a function of bidirectional information transmission, services it provides are limited and most of the services are provided unidirectionally from information providers. Furthermore, each central equipment provides its own particular information so that if the equipment has no information desired by a subscriber, the subscriber has to inquire for the information from another information provider via a telephone exchange.